Photojournalists working in areas of conflict around the world - Juarez, Mexico; South Sudan; Libya and Rio de Janeiro - are the heart of "Witness," four films that will air on HBO over the next four Mondays.

"We live in a moment of lies," says a colleague of slain Brazilian journalist Tim Lopes, in the new documentary series "Witness." In 2002, Lopes was dismembered while still alive and then burned to death within a "microonda," a favored method of body disposal by drug traffickers in Rio de Janeiro. The word translates as "microwave."

Cristina Guimdraes is speaking to Eros Hoagland, one of the profiled photojournalists working in areas of conflict around the world: Juarez, Mexico; South Sudan; Libya and Rio de Janeiro. Produced by Michael Mann ("Luck," "Ali") and David Frankham, the four films will air on HBO over the next four Mondays.

With his scruffy good looks and unflappably reserved demeanor, Hoagland looks the part of the world-trekking photographer that he is. In a career that began in 1993 covering the aftermath of the war in El Salvador, Hoagland has toured many notorious hot spots — Afghanistan, Haiti, the Middle East — but Mexico, Central and South America seem to be his career's "center of gravity," he says.

He doesn't have to make the connection in words to the death of his dad, Newsweek photographer John Hoagland, who was killed in 1984 while covering the war in El Salvador.

Eros Hoagland inherited both his father's equipment and his drive to document areas of turmoil. He is motivated in part because he wanted to understand what took his dad away from their San Diego home so often. Now he knows, and it's the same thing that drives him, as well was the other photographers in the HBO series.

The moment of lies cited above refers to the "pacification" project taking place in Rio in advance of the city hosting the World Cup in 2014 and the Olympics two years later. The city that sprawls beneath the outspread welcoming arms of the towering Christ the Redeemer statue is, in fact, many cities. Tourists know the Copacabana beach, but they steer clear of the 900 "favelas" — gang-ruled slum fiefdoms — crawling up the surrounding hillsides. The government is trying to "pacify" the less picturesque areas of the city, slum by slum, before the world's attention focuses on Rio in 2014.

Hoagland's job is to document moments of lies truthfully.

It doesn't come easily, not just because he's literally putting his life in danger when he treks into the middle of favelas in Rio, or when he photographs the drug-related murders in Ciudad Juarez, directly across the U.S. border in Mexico. But also because even though he relies on his camera as a "shield" between himself and what he is photographing, what he sees through his viewfinder takes an inevitable emotional toll.

Hoagland's job, he says, is "not to mourn for (the victim)" or console the survivors: He is "there to document it."

French photographer Veronique de Viguerie, pregnant as she traipses through the jungles of central Africa with the "Arrow Boys" fighting against Ugandan Joseph Kony's Lord's Resistance Army, wrestles with the same issues as Hoagland. In the "Witness" film airing Nov. 19, De Viguerie, whose boyfriend had died at 33 of a heart attack in her arms, accompanies the ragtag resistance fighters at night following the trail of the Lord's Resistance Army.

"If someone is dying in front of you, do you take pictures or help them?" she asks. "I'm a human first and a photographer second, isn't it?"

At every turn in this heart-wrenching series of films, we are reminded that these men and women are human, no matter how robotic they may seem as they rapidly snap off shots of death and tears. It is because they are human that their photographs have meaning and convey truths.

One of the many stunning features of the films is how the deeply eloquent work of the three photographers augments the video footage.

Two of the three photographers featured carry significant internal burdens of loss. The third, Michael Christopher Brown, is younger, but was in Libya five times during the revolt that eventually brought an end to Moammar Khadafy's four-decade dictatorship.

If Brown didn't have his own internal burden of loss before, he does now. It is, to paraphrase author Tim O'Brien, one of the things he carries.